Fallacy of zero-extinction targets

20 05 2022

Nearly a decade ago (my how time flies*), I wrote a post about the guaranteed failure of government policies purporting no-extinction targets within their environmental plans. I was referring to the State of South Australia’s (then) official policy of no future extinctions.

In summary, zero- (or no-) extinction targets at best demonstrate a deep naïvety of how ecology works, and at worst, waste a lot of resources on interventions doomed to fail.

1. Extinctions happen all the time, irrespective of human activity;

2. Through past environmental degradation, we are guaranteed to see future extinctions because of extinction lags;

3. Few, if any, of the indicators of biodiversity change show improvement.

4. Climate change will also guarantee additional (perhaps even most) future extinctions irrespective of Australian policies.

I argued that no-extinction policies are therefore disingenuous to the public in the extreme because they sets false expectations, engender disillusionment after inevitable failure, and ignores the concept of triage — putting our environment-restoration resources toward the species/systems with the best chance of surviving (uniqueness notwithstanding).

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A cascade of otters

4 04 2022

Carnivores are essential components of trophic webs, and ecosystem functions crumble with their loss. Novel data show the connection between calcareous reefs and sea otters under climate change.


Trophic cascade on the Aleutian Islands (Alaska, USA) linking sea otters (Enhydra lutris) with sea urchins (Strongylocentrotus polyacanthus) and calcareous reefs (Clathromorphum nereostratum). With males weighting up to 50 kg, sea otters have been IUCN-catalogued as Endangered since 2000. The top photo shows a male in a typical, belly-up floating position. The bottom photo shows live (pinkish) and dead (whitish) tissue on the reef surface as a result of grazing of sea urchins at a depth of 10 m. Sea otters are mesopredators, typically foraging on small prey like sea urchins, but their historical decline due to overhunting unleashed the proliferation of the echinoderms. At the same time, acidification and sea-water warming have softened the skeleton of the reefs, allowing for deeper grazing by sea urchins that eliminate the growth layer of living tissue that give the reefs their pinkish hue. Large extents of dead reefs stop fixing the excess in carbonic acid, whose carbon atoms sea water sequesters from the atmosphere enriched in carbon by our burning of fossil fuels. Photos courtesy of Joe Tomoleoni taken in Moss Landing – California, USA (otter), and on the Near Islands – Aleutian Archipelago, Alaska (reef).

For most, the decisions made by people we have never met affect our daily lives. Other species experience the same phenomenon because they are linked to one another through a trophic cascade.

A trophic cascade occurs when a predator limits the abundance or behaviour of its prey, in turn affecting the survival of a third species in lower trophic levels that have nothing directly to do with the predator in question (1).

Sea otters (Enhydra lutris) represent a text-book example of a trophic cascade. These mustelids (see video footage here and here) hunt and control the populations of sea urchins (Strongylocentrotus polyacanthus), hence favouring kelp forests  — the fronds of which are eaten by the sea urchins.

Removing the predator from the equation should lead to more sea urchins and less kelp, and this chain of events is exactly what happened along the coasts of the North Pacific (2, 3). The historical distribution of sea otters once ranged from Japan to Baja California through the Aleutian Islands (see NASA’s photo from space, and documentary on the island of Unimak), a sub-Arctic, arc-shaped archipelago including > 300 islands between Alaska (USA) and the Kamchatka Peninsula (Russia), extending ~ 2000 kilometres, and having a land area of ~ 18,000 km2.

But the fur trade during the 18th and 19th centuries brought the species to the brink of extinction, down to < 2000 surviving individuals (4). Without otters, sea urchins boomed and deforested kelp ecosystems during the 20th Century (5). Now we also know that this trophic cascade has climate-related implications in other parts of the marine ecosystem.

Underwater bites

Doug Rasher and collaborators have studied the phenomenon on the Aleutian Islands (6). The seabed of this archipelago is a mix of sandy beds, kelp forests, and calcareous reefs made up of calcium and magnesium carbonates fixed by the red algae Clathromorphum nereostratum. These reefs have grown at a rate of 3 cm annually for centuries as the fine film of living tissue covering the reef takes the carbonates from the seawater (7).

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Be wise about what you put online

21 03 2022

While you have little choice these days about posting your data and code online when you publish, here are some things to consider when contemplating putting potentially sensitive data online (modified excerpt from The Effective Scientist).


One aspect of making your data publicly available is the prickly issue of whether your data contain sensitive information.

Of course, there are many different types of ‘sensitive’ information that might accompany the more basic quantitative measurements of your datasets, with perhaps the most common being personal details of any human subjects. For example, if you are a medical researcher and your data are derived primarily from living human beings undergoing some procedure, trial, or intervention, then clearly you are bound by your human ethics approvals not to publish information like names, addresses, or anything that could be used to identify the subjects in your sample. In fact, human ethics approvals generally prohibit any sort of public accessibility to medical data that has personal information included; thus, the scientists concerned are being pulled in two different directions — keeping their subjects’ personal information out of the hands of the public, while still making the data available to other scientists.

There are ways around this, such as publishing only generic information online (i.e., by excluding personal identifiers) that could then be linked to the more sensitive data via unique identifiers. In these cases, any other researcher requiring the additional information would have to seek specific permission from the primary researchers, pending additional human-ethics approvals.

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Can we resurrect the thylacine? Maybe, but it won’t help the global extinction crisis

9 03 2022

NFSA

(published first on The Conversation)

Last week, researchers at the University of Melbourne announced that thylacines or Tasmanian tigers, the Australian marsupial predators extinct since the 1930s, could one day be ushered back to life.

The thylacine (Thylacinus cynocephalus), also known as the ‘Tasmanian tiger’ (it was neither Tasmanian, because it was once common in mainland Australia, nor was it related to the tiger), went extinct in Tasmania in the 1930s from persecution by farmers and habitat loss. Art by Eleanor (Nellie) Pease, University of Queensland.
Centre of Excellence for Australian Biodiversity and Heritage

The main reason for the optimism was the receipt of a A$5 million philanthropic donation to the research team behind the endeavour.

Advances in mapping the genome of the thylacine and its living relative the numbat have made the prospect of re-animating the species seem real. As an ecologist, I would personally relish the opportunity to see a living specimen.

The announcement led to some overhyped headlines about the imminent resurrection of the species. But the idea of “de-extinction” faces a variety of technical, ethical and ecological challenges. Critics (like myself) argue it diverts attention and resources from the urgent and achievable task of preventing still-living species from becoming extinct.

The rebirth of the bucardo

The idea of de-extinction goes back at least to the the creation of the San Diego Frozen Zoo in the early 1970s. This project aimed to freeze blood, DNA, tissue, cells, eggs and sperm from exotic and endangered species in the hope of one day recreating them.

The notion gained broad public attention with the first of the Jurassic Park films in 1993. The famous cloning of Dolly the sheep reported in 1996 created a sense that the necessary know-how wasn’t too far off.

The next technological leap came in 2008, with the cloning of a dead mouse that had been frozen at –20℃ for 16 years. If frozen individuals could be cloned, re-animation of a whole species seemed possible.

After this achievement, de-extinction began to look like a potential way to tackle the modern global extinction crisis.

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The sixth mass extinction is happening now, and it doesn’t look good for us

2 03 2022

Mounting evidence is pointing to the world having entered a sixth mass extinction. If the current rate of extinction continues we could lose most species by 2200. The implication for human health and wellbeing is dire, but not inevitable.

In the timeline of fossil evidence going right back to the first inkling of any life on Earth — over 3.5 billion years ago — almost 99 percent of all species that have ever existed are now extinct. That means that as species evolve over time — a process known as ‘speciation’ — they replace other species that go extinct.

Extinctions and speciations do not happen at uniform rates through time; instead, they tend to occur in large pulses interspersed by long periods of relative stability. These extinction pulses are what scientists refer to as mass extinction events.

The Cambrian explosion was a burst of speciation some 540 million years ago. Since then, at least five mass extinction events have been identified in the fossil record (and probably scores of smaller ones). Arguably the most infamous of these was when a giant asteroid smashed into Earth about 66 million years ago in what is now the Gulf of Mexico. The collision vapourised species immediately within the blast zone. Later, species were killed off by climate change arising from pulverised particulates suspended in the atmosphere, as well as intense volcano activity stimulated by the buckling of the Earth’s crust from the asteroid’s impact. Together, about 76 percent of all species around at the time went extinct, of which the disappearance of the dinosaurs is most well-known. But dinosaurs didn’t disappear altogether — the survivors just evolved into birds.

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Cartoon guide to biodiversity loss LXX

16 02 2022

Here is the first set of biodiversity cartoons for 2022. See full stock of previous ‘Cartoon guide to biodiversity loss’ compendia here.


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Influential conservation papers of 2021

5 01 2022

Following my annual tradition, I present the retrospective list of the ‘top’ 20 influential papers of 2021 as assessed by experts in Faculty Opinions (formerly known as F1000). These are in no particular order. See previous years’ lists here: 2020, 201920182017201620152014, and 2013.


Amazonia as a carbon source linked to deforestation and climate change — “… confirms what the sparse forest inventory has suggested, that climate change and land-use change is driving Amazonian ecosystems toward carbon sinks. … the research team provides a robust estimate of the carbon dynamics of one of the world’s most important ecosystems and provides insights into the role of land use change and potentials for mitigating direct carbon losses in the future.

Organic and conservation agriculture promote ecosystem multifunctionality — “… a very clear insight into the trade-offs between the different ecosystem services and indicate that yield and product quality are lower in organic systems compared to conventional systems, yet organic systems have higher economic performance due to higher product prices and subsidies.

Biodiversity of coral reef cryptobiota shuffles but does not decline under the combined stressors of ocean warming and acidification — “… even with similar richness, community function is very likely to be perturbed by ocean warming/acidification with unpredictable impacts on economically important species such as fish and corals.

Local conditions magnify coral loss after marine heatwaves — “… show that climate-induced coral loss is greater in areas with elevated seaweed abundance and elevated sea urchin densities, both of which commonly result from local overfishing … effective local management can synergize with global efforts to mitigate climate change and help coral reefs survive the Anthropocene.

Large ecosystem-scale effects of restoration fail to mitigate impacts of land-use legacies in longleaf pine savannas — “… while restoration can have major benefits in longleaf savannas, land-use legacies have clear effects on many aspects of the ecosystem.

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Fancy a pangolin infected with coronavirus? Apparently, many people do

30 12 2021

The logic of money contradicts the logic of species conservation and human health. As illegal trade has driven pangolins to near extinction, their hunting and market value has kept increasing ― even when we have known that they act as coronavirus reservoirs in the middle of the Covid-19 pandemic.

Sunda pangolin (Manis javanica) in a monsoon forest (Sumba Island, Indonesia). With adult weights up to 10 kg and body lengths around half a metre, these animals are mostly solitary and nocturnal, feed on ants and termites, and love tree climbing using bark hollows to shelter and give birth to singletons. The species occurs across mainland and islands of South East Asia, and became ‘Endangered’ in 2008 and ‘Critically Endangered’ in 2014, following a 80% decline in the last 20 years due to hunting and poaching. It has been the most heavily trafficked Asian species, and the IUCN’s assessment states: “… the incentives for harvesting and illegally trading in the species are universally high based on the high financial value of pangolin parts and derivatives”. Captive breeding is unlikely to deter wild collection because (among other reasons) farming costs are high (more so on a large scale) and, even if the species could be traded legally, wild versus farmed pangolin products and individuals are difficult to distinguish (23). Photo courtesy of Michael Pitts

Urbanites are attracted to exotic species, materials, and places. Our purchasing power seems to give us the right to buy any ‘object’ that we can pay for, no matter how exotic the object might be. In such a capitalist rationale, it is no surprise that > 150 thousand illegal cargos with wild animals and plants have been confiscated in 149 countries over the last two decades, moving some 6000 species from one place of the planet to another (1).

Social networks show people interacting with all kinds of fauna, creating the illusion that any animal can become a pet (2). And there’s a multi-$billion market of wildlife for a diverse array of uses including collecting, food, ornamentation, leisure, clothing and medicine (3-5). The paradox is that the rarer a species is, the higher its market value runs and the more lucrative selling it turns out to be, leading to more exploitation and rocketing extinction risk (6).

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Cartoon guide to biodiversity loss LXIX

23 12 2021

Here is the final set of biodiversity cartoons for 2021, with some à propos seasonal content. See full stock of previous ‘Cartoon guide to biodiversity loss’ compendia here.


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Remote areas not necessarily safe havens for biodiversity

16 12 2021

The intensity of threats to biodiversity from human endeavour becomes weaker as the distance to them increases.


As you move away from the big city to enjoy the countryside, you’ll notice the obvious increase in biodiversity. Even the data strongly support this otherwise subjective perception — there is a positive correlation between the degree we destroy habitat, harvest species, and pollute the environment, and the distance from big cities.

Remote locations are therefore usually considered safe havens and potential reservoirs for biodiversity. But our new study published recently in Nature Communications shows how this obvious pattern depicts only half of the story, and that global conservation management and actions might benefit from learning more about the missing part.

Communities are not just lists of individual species. Instead, they consist of complex networks of ecological interactions linking interdependent species. The structure of such networks is a fundamental determinant of biodiversity emergence and maintenance. However, it also plays an essential role in the processes of biodiversity loss. The decline or disappearance of some species might have detrimental —often fatal — effects on their associates. For example, a parasite cannot survive without its hosts, as much as a predator will starve without prey, or a plant will not reproduce without pollinators.

Events where a species disappears following the loss of other species on which it depends are known as co-extinctions, and they are now recognised as a primary driver of the ongoing global biodiversity crisis. The potential risk stemming from ecological dependencies is a major concern for all ecological systems.

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An eye on the past: a view to the future

29 11 2021

originally published in Brave Minds, Flinders University’s research-news publication (text by David Sly)

Clues to understanding human interactions with global ecosystems already exist. The challenge is to read them more accurately so we can design the best path forward for a world beset by species extinctions and the repercussions of global warming.


This is the puzzle being solved by Professor Corey Bradshaw, head of the Global Ecology Lab at Flinders University. By developing complex computer modelling and steering a vast international cohort of collaborators, he is developing research that can influence environmental policy — from reconstructing the past to revealing insights of the future.

As an ecologist, he aims both to reconstruct and project how ecosystems adapt, how they are maintained, and how they change. Human intervention is pivotal to this understanding, so Professor Bradshaw casts his gaze back to when humans first entered a landscape – and this has helped construct an entirely fresh view of how Aboriginal people first came to Australia, up to 75,000 years ago.

Two recent papers he co-authored — ‘Stochastic models support rapid peopling of Late Pleistocene Sahul‘, published in Nature Communications, and ‘Landscape rules predict optimal super-highways for the first peopling of Sahul‘ published in Nature Human Behaviour — showed where, how and when Indigenous Australians first settled in Sahul, which is the combined mega-continent that joined Australia with New Guinea in the Pleistocene era, when sea levels were lower than today.

Professor Bradshaw and colleagues identified and tested more than 125 billion possible pathways using rigorous computational analysis in the largest movement-simulation project ever attempted, with the pathways compared to the oldest known archaeological sites as a means of distinguishing the most likely routes.

The study revealed that the first Indigenous people not only survived but thrived in harsh environments, providing further evidence of the capacity and resilience of the ancestors of Indigenous people, and suggests large, well-organised groups were able to navigate tough terrain.

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Citizens meet coral gardening

12 10 2021

It is possible to cultivate corals in the sea like growing a nursery of trees to restore a burned forest. Cultivated corals grow faster than wild corals and can be outplanted to increase the healthy area of damaged reefs. Incorporated in projects of citizen science and ecotourism, this activity promotes environmental awareness about coral reefs, the marine ecosystem that is both the most biodiverse and the most threatened by global change.


When I finished by undergraduate studies in the 1980s, I met several top Spanish marine biologists to prospect my first job ever in academia. In all one-to-one interviews I had, I was asked what my interests were. And when I described that I wanted to study ways of modifying impacted marine ecosystems to restore their biodiversity, a well-known professor judged that my proposition was an inviable form of jardinería marina (marine gardening) ― those words made me feel embarrassed and have remained vivid in my professional imagination since. Neither the expert nor the young researcher knew at the time that we were actually talking about ecological restoration, a discipline that was being formalised exactly then by botanists in their pledge to recover pre-European conditions for North American grasslands (1).

Aspects of coral gardening. The photos show (top) a diver scraping off (with the aid of a toothbrush) algae, sponges and parasites that compete for light and nutrients with the coral fragments under cultivation along suspended ropes (Cousin Island, Seychelles), (middle) coral outplantings in the Gulf of Eliat (Red Sea) hosting a diverse community of fish that clean off the biofouling for free (21), and (bottom) a donor colony farmed off Onna (Okinawa, Japan) (12). Photos courtesy of Luca Saponari (Cousin), Buki Rinkevich (Eliat) and Yoshimi Higa / Onna Village Fishery Cooperative.

Today, the term coral gardening encompasses the suite of methods to cultivate corals (tiny colonial jellyfish with an external skeleton and a carnivorous diet) and to outplant them into the wild to boost the growth of coral reefs following perturbations (2). In the face of the decline of coral reefs globally, due to the combination of climate change, pollution, and overfishing (3), this type of mariculture has gathered momentum in the last three decades and is currently being applied to more than 100 coral species in all the main reefs of our seas and oceans (4-6).

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Avoiding a ghastly future — The Science Show

1 10 2021

Just thought I’d share the audio of an interview I did with the famous Robyn Williams of ABC Radio National‘s The Science Show.

I’d be surprised if any Australians with even a passing interest in science could claim not to have listened to the Science Show before, and I suspect a fair mob of people overseas would be in the same boat.

It was a real privilege to talk with Robyn about our work on the ghastly future, and as always, the production value is outstanding.

Thank you, Robyn and the ABC.

Listen below, or link to the interview directly.





The very worn slur of “neo-Malthusian”

7 09 2021

After the rather astounding response to our Ghastly Future paper published in January this year (> 443,000 views and counting; 61 citations and counting), we received a Commentary that was rather critical of our article.

A Malthusian slur

We have finally published a Response to the Commentary, which is now available online (accepted version) in Frontiers in Conservation Science. Given that it is published under a Creative Commons Attribution License (CC BY), I can repost the Response here:


In their comment on our paper Underestimating the challenges of avoiding a ghastly future, Bluwstein et al.2 attempt to contravene our exposé of the enormous challenges facing the entire human population from a rapidly degrading global environment. While we broadly agree with the need for multi-disciplinary solutions, and we worry deeply about the inequality of those who pay the costs of biodiversity loss and ecological collapse, we feel obligated to correct misconceptions and incorrect statements that Bluwstein et al.2 made about our original article.

After incorrectly assuming that our message implied the existence of “one science” and a “united scientific community”, the final paragraph of their comment contradicts their own charge by calling for the scientific community to “… stand in solidarity”. Of course, there is no “one science” — we never made such a claim. Science is by its nature necessarily untidy because it is a bottom-up process driven by different individuals, cultures, perspectives, and goals. But it is solid at the core. Scientific confluence is reached by curiosity, rigorous testing of assumptions, and search for contradictions, leading to many — sometimes counter-intuitive or even conflicting — insights about how the world works. There is no one body of scientific knowledge, even though there is good chance that disagreements are eventually resolved by updated, better evidence, although perhaps too slowly. That was, in fact, a main message of our original article — that obligatory specialisation of disparate scientific fields, embedded within a highly unequal and complex socio-cultural-economic framework, reduces the capacity of society to appreciate, measure, and potentially counter the complexity of its interacting existential challenges. We agree that scientists play a role in political struggles, but we never claimed, as Bluwstein et al.2 contended, that such struggles can be “… reduced to science-led processes of positive change”. Indeed, this is exactly the reason our paper emphasized the political impotence surrounding the required responses. We obviously recognize the essential role social scientists play in creating solutions to avoid a ghastly future. Science can only provide the best available evidence that individuals and policymakers can elect to use to inform their decisions. 

We certainly recognise that there is no single policy or polity capable of addressing compounding and mounting problems, and we agree that that there is no “universal understanding of the intertwined socio-ecological challenges we face”. Bluwstein et al.2 claimed that we had suggested scientific messaging alone can “… adequately communicate to the public how socio-ecological crises should be addressed”. We did not state or imply such ideas of unilateral scientific power anywhere in our article. Indeed, the point of framing our message as pertaining to a complex adaptive system means that we cannot, and should not, work towards a single goal. Instead, humanity will be more successful tackling challenges simultaneously and from multiple perspectives, by exploiting manifold institutions, technologies, approaches, and governances to match the complexity of the predicament we are attempting to resolve.

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It’s a tough time for young conservation scientists

24 08 2021

Sure, it’s a tough time for everyone, isn’t it? But it’s a lot worse for the already disadvantaged, and it’s only going to go downhill from here. I suppose that most people who read this blog can certainly think of myriad ways they are, in fact, still privileged and very fortunate (I know that I am).

Nonetheless, quite a few of us I suspect are rather ground down by the onslaught of bad news, some of which I’ve been responsible for perpetuating myself. Add lock downs, dwindling job security, and the prospect of dying tragically due to lung infection, many have become exasperated.

I once wrote that being a conservation scientist is a particularly depressing job, because in our case, knowledge is a source of despair. But as I’ve shifted my focus from ‘preventing disaster’ to trying to lessen the degree of future shittyness, I find it easier to get out of bed in the morning.

What can we do in addition to shifting our focus to making the future a little less shitty than it could otherwise be? I have a few tips that you might find useful:

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Pest plants and animals cost Australia around $25 billion a year — and it will get worse

2 08 2021
AAP

Corey J. A. Bradshaw, Flinders University and Andrew Hoskins, CSIRO

This article is republished from The Conversation under a Creative Commons licence. Read the original article.


Shamefully, Australia has one of the highest extinction rates in the world.
And the number one threat to our species is invasive or “alien” plants and animals.

But invasive species don’t just cause extinctions and biodiversity loss – they also create a serious economic burden. Our research, published today, reveals invasive species have cost the Australian economy at least A$390 billion in the last 60 years alone.

Our paper – the most detailed assessment of its type ever published in this country – also reveals feral cats are the worst invasive species in terms of total costs, followed by rabbits and fire ants.

Without urgent action, Australia will continue to lose billions of dollars every year on invasive species.

Feral cats are Australia’s costliest invasive species. Source: Adobe Stock/240188862

Huge economic burden

Invasive species are those not native to a particular ecosystem. They are introduced either by accident or on purpose and become pests.

Some costs involve direct damage to agriculture, such as insects or fungi destroying fruit. Other examples include measures to control invasive species like feral cats and cane toads, such as paying field staff and buying fuel, ammunition, traps and poisons.

Our previous research put the global cost of invasive species at A$1.7 trillion. But this is most certainly a gross underestimate because so many data are missing.


Read more:
Attack of the alien invaders: pest plants and animals leave a frightening $1.7 trillion bill


As a wealthy nation, Australia has accumulated more reliable cost data than most other regions. These costs have increased exponentially over time – up to sixfold each decade since the 1970s.

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‘Living’ figures

8 07 2021

Have you ever constructed a database and then published the findings, only to realise that after the time elapsed your database is already obsolete?

This is the reality of scientific information today. There are so many of us doing so many things that information accumulates substantially in months, if not weeks. If you’re a geneticist, this probably happens for many datasets on the order of days.

While our general databasing capacity worldwide has improved enormously over the last decade with the transition to fully online and web-capable interactivity, the world of scientific publication still generally lags behind the tech. But there is a better way to communicate dynamic, evolving database results to the public.

Enter the ‘living figure’, which is a simple-enough concept where a published figure remains dynamic as its underlying database is updated.

We have, in fact, just published such a living figure based on our paper earlier this year where we reported the global costs of invasive species.

That paper was published based on version 1 of the InvaCost database, but a mere three months after publication, InvaCost is already at version 4.

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Losing half of tropical fish species as corals disappear

30 06 2021

When snorkelling in a reef, it’s natural to think of coral colonies as a colourful scenography where fish act in a play. But what would happen to the fish if the stage went suddenly empty, as in Peter Brook’s 1971 Midsummer Night’s Dream? Would the fish still be there acting their roles without a backdrop?


This question is not novel in coral-reef science. Ecologists have often compared reef fish diversity and biomass in selected localities before and after severe events of coral mortality. Even a temporary disappearance of corals might have substantial effects on fish communities, sometimes resulting in a local disappearance of more than half of local fish species.

Considering the multiple, complex ways fish interact with — and depend on — corals, this might appear as an obvious outcome. Still, such complexity of interactions makes it difficult to predict how the loss of corals might affect fish diversity in specific contexts, let alone at the global scale.

Focusing on species-specific fish-coral associations reveals an inconsistent picture with local-scale empirical observations. When looking at the fraction of local fish diversity that strictly depends on corals for food and other more generic habitat requirements (such as shelter and reproduction), the global picture suggests that most fish diversity in reef locality might persist in the absence of corals. 

The mismatch between this result and the empirical evidence of a stronger coral dependence suggests the existence of many hidden ecological paths connecting fish to corals, and that those paths might entrap many fish species for which the association to corals is not apparent.

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Is the IPCC finally catching up with the true severity of climate change?

24 06 2021

I’m not in any way formally involved in either the IPCC or IPBES, although I’ve been involved indirectly in analysing many elements of both the language of the reports and the science underlying their predictions.


Today, The Guardian reported that a leaked copy of an IPCC report scheduled for release soon indicated that, well, the climate-change situation is in fact worse than has been previously reported in IPCC documents.

If you’re a biologist, climatologist, or otherwise-informed person, this won’t come as much of a surprise. Why? Well, the latest report finally recognises that the biosphere is not just some big balloon that slowly inflates or deflates with the whims of long-term climate variation. Instead, climate records over millions of years show that the global climate can and often does shift rapidly between different states.

This is the concept of ‘tipping points’.

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Everything you always wanted to know about conservation (but were afraid to ask)

14 05 2021

While some of us still might imagine the conservationist as a fancy explorer discovering new species in a remote corner of the world, or collecting samples while drowning in mud, a growing portion of conservation science nowadays consists of asking people about their ideas and behaviours.

Needless to say, this approach produces a fair share of awkward, if not dangerous, situations. After all, who likes the idea of completing a questionnaire from the fisheries office, asking about compliance with harvest limitations or licence fees? Or, even worse, who fancies being asked about the possession of illegally traded wildlife? 

Many conservationists would really like to have this valuable information, but at the same time it is clear that these questions put people at great discomfort. This leads to biased estimates of important behaviours affecting conservation. This is where specialised questioning techniques can help.

Specialised questioning techniques aim to prevent researchers, or anyone else, to trace back individual answers. Many do so by adding noise with a known distribution to individual answers. Then, when all answers are pooled, this noise is ruled out with statistical approaches. Noise can come from a randomising device (e.g. a die), like in the randomised response technique:

Individual answers can also be masked by asking respondents not to indicate if they engaged in a certain behaviour, but by asking them, out of a list of sensitive and non-sensitive behaviours, to indicate the number in which they engaged. This is the case of the unmatched count technique (a.k.a list experiments):

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